Interactions of the Pacific ocean variability with western U.S. streamflow.

Abstract:

Study of impacts of climate variability on streamflow is necessitated by the growing need for better water management. The western U.S. is mostly arid in the southwest, experiences heavy precipitation in the northwest, and influenced by the moisture coming from the Pacific Ocean. A study of the interactions between the Pacific Ocean climate variability and western U.S. streamflow is presented. Singular value decomposition (SVD) technique is used to evaluate the influence of winter season sea surface temperature (SST) on seasonal i.e., spring, summer, and spring-summer streamflow in six hydrologic regions in the western United States for 50 years (1960-2010). A lagged lead time approach was utilized i.e., previous year October to December SST were used to predict current year spring-summer (April to September), spring (April to June), and summer (July to September) streamflow for each hydrologic region. The variability in terms of lagged response of adjacent watersheds was established, which can be attributed to spatial and local factors. The temporal expansion series generated from SVD lead to high correlation values for spring-summer streamflow in the western United States. The SVD technique was applied to the six regions taken together, which addressed the bias generated when using global datasets. The results obtained from this study can be used to improve the current forecasting techniques for streamflow.

Key words: Streamflow, Sea surface temperature, Singular value decomposition